我对android dev几乎是新手。
我试图在片段中设置自定义键盘视图但是在＆＃34; setKeyboard（..）应用程序崩溃。我究竟做错了什么？ 下面的代码和logcat监视器。谢谢大家。
CustomKeyboard类：
public class CustomKeyboard {
private KeyboardView mKeyboardView;
private Activity mHostActivity;
private View mRootView;
private KeyboardView.OnKeyboardActionListener mOnKeyboardActionListener;
public CustomKeyboard(Activity host, View rootView, int viewId,
int layoutId) {
mHostActivity= host;
mRootView = rootView;
mKeyboardView= (KeyboardView)mRootView.findViewById(viewId);
mKeyboardView.setKeyboard(new Keyboard(mHostActivity, layoutId));
mKeyboardView.setPreviewEnabled(false);
mKeyboardView.setOnKeyboardActionListener(mOnKeyboardActionListener);
mHostActivity.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
}
}
片段：
public class FragmentGame extends ListFragment {
private CustomKeyboard customKeyboard;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = super.onCreateView(inflater, container, savedInstanceState);
...
...
//create the keyboard andd attach to keyboardview
customKeyboard = new CustomKeyboard(getActivity(), v, R.id.keyboardview,
R.xml.keyboard);
return v;
}
}
片段布局：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:id="@+id/listview_game_items"
android:layout_width="match_parent"
android:layout_height="match_parent">
</ListView>
<android.inputmethodservice.KeyboardView
android:id="@+id/keyboardview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom = "true"
android:visibility="gone"
/>
</RelativeLayout>
logcat的：
FATAL EXCEPTION: main
Process: com.gontavahl.mtgsync, PID: 19983
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.inputmethodservice.KeyboardView.setKeyboard(android.inputmethodservice.Keyboard)' on a null object reference
at com.gontavahl.mtgsync.CustomKeyboard.<init>(CustomKeyboard.java:25)
at com.gontavahl.mtgsync.FragmentGame.onCreateView(FragmentGame.java:36)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1974)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1252)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:742)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1617)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1177)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1025)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1545)
at android.view.View.measure(View.java:17565)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5537)
at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:668)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:735)
at android.view.View.measure(View.java:17565)
at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:1075)
at android.view.View.measure(View.java:17565)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5537)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
at android.view.View.measure(View.java:17565)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5537)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17565)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5537)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.view.View.measure(View.java:17565)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5537)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17565)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5537)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2615)
at android.view.View.measure(View.java:17565)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2045)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1811)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1084)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5990)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5343)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905)